\begin{table}%t1
\caption{\label{JournalYears}Summary of observations for each year.}\vspace*{-1mm}
%\centering
\par
\begin{tabular}{*{8}{c}}
\hline \hline \noalign{\smallskip}
Year   & $T$   &   $n_{\rm on}$ &  $n_{\rm off}$ &   Excess&  $\sigma$ & $\sigma/\!\sqrt{T}$ \\ 
   \hline
2005 & 9.4 &  7282 & 27~071 &  1868 &  21.8 &   7.1 \\
2006 & 66.1 & 123~567 & 203~815 & 82~804 & 288.4 &  35.5 \\
2007 & 13.8 & 11~012 & 40~065 &  2999 &  28.6 &   7.7 \\
   \hline
Total & 89.2 & 141~861 & 270~951 & 87~671 & 275.6 &  29.2 \\
\hline
\end{tabular}\vspace*{-2mm}
\tablefoot{$T$~represents the live-time (hours), $n_{\rm on}$~the number of on-source events, $n_{\rm off}$~the number of off-source events (from a region five times larger than for the on-source events), and~$\sigma$ the significance of the corresponding excess, given in units of standard deviations.}
\end{table}